A journey through time: Digitizing, processing and ...around 400’000 aerial images (starting 1926)...
Transcript of A journey through time: Digitizing, processing and ...around 400’000 aerial images (starting 1926)...
A journey through time: Digitizing, processing
and publishing historical aerial imagery in
Switzerland
- The 1946 Showcase
Holger Heisig, Philip Jörg, André Streilein
EuroSDR Workshop on Geoprocessing and Archiving of Historical Aerial
Images
IGN headquarters | 94165 Saint-Mandé, France, 3rd – 4th June 2019
Media reception
Swiss online media titles from 21 & 22 May 2019
Swiss online media titles from 21 & 22 May 2019
Swiss online media titles from 21 & 22 May 2019
• «New» Ortho-mosaic released: Switzerland in 1946
• Unique and country-wide ortho-photo coverage
• Snapshot of a long disappeared landscape
• Basis for the general public and research to make the enormous
changes in the Swiss landscape visible.
• Convenient and fast online viewing and comparing
• Published and promoted through press release on 21 May 2019
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Why so much media attention?
2. The products
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Technical properties Coverage: 99.78%. Ground resolution: 1 m Average position accuracy: 5 – 10 m
The 1946 PhotoAtlas
Online viewing and comparing
• Central platform: www.maps.ch
• 4 languages (English, French, German, Italian)
• Search for dataset, e.g. “1946”
• Display “SWISSIMAGE HIST 1946” dataset
• Use Advanced tools/ Compare to compare with most recent Orthodata
or map data
Online viewing and comparison
Some interesting changes
• https://s.geo.admin.ch/81e15c2760
• https://s.geo.admin.ch/81e1607ffc
• https://s.geo.admin.ch/81e161c330
• https://s.geo.admin.ch/81e1631d91
• https://s.geo.admin.ch/81e164488d
• https://s.geo.admin.ch/81e1664fa3
• https://s.geo.admin.ch/81e167c987
Querying metadata of acquisitions
But still printable
3. Historic Context
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Not bombing but photography
Robert J. Boyd: Project «Casey Jones» 1945–1946. Post-Hostilities Aerial Mapping; Iceland, Europe, North Africa June 1945 – December 1946
[1988], 61 S.
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Project «Casey Jones» 1945–1946
• Named after American aviation pioneer Charles S. «Casey» Jones (11.1.1894–2.2.1976)
• Mid 1944: Start of planning («top secret»)
• Gigantic (photo) mapping project
- over 2 million square miles - 66 participating aircraft
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Project «Casey Jones» 1945–1946
Common project of
• US Army Air Force USAAF
• RAF Royal Air Force (UK)
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45–
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RAF USAAF 50° 20’
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Diplomatic agreements with Switzerland
Schweizerisches Bundesarchiv BAR E27 / 22042
• Creation of a world map 1:1'000'000 for international
and intercontinental aviation
• Most of the aerial photographs in Europe have already
been completed or are in the process of being
completed.
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Schweizerisches Bundesarchiv BAR E27 / 22042
• American aircraft with - if desired - Swiss observers on
board
• A copy of the negatives would be made available to
the Swiss authorities.
Diplomatic agreements with Switzerland
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Chronology of US Army Air Force Image acquisition in 1946
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Recording Aircraft Boeing B-17 G
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Armament removed,
gaps closed with glass
Camera location in the floor of the radio room
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«Mount Camera Vertical» Typ A–11
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Camera 1
detail viewfinder
Camera 2
Intervallometer
caméra entièrement automatique
format des photos 23 x 23 cm
distances focales 15/30/60/100 cm
toutes les photos avec 15 cm (95°)
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Navigator in the nose of Boeing B-17 G
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View from the nose sideways
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4. The photo archives
• collection period: late 19th to early
21st century
• scope: Approximately half a
million analog recordings
• a valuable treasure of historical
geodata and part of Switzerland's
landscape memory.
• shall be preserved and made
available to the public in its
entirety.
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The image collection of swisstopo
Conservation & Scanning plan of aerial imagery
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Film with lettering:
Signature of the recording
Type of the original film:
"3935 EASTMAN
TOPOGRAPHIC SAFETY"
"Safety" = not fire
endangered
Duplicate negative on nitrate
film!
Materiality and condition of the 1946 negatives
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Left: Film in the original cover
Right: swelling of the film
Materiality and condition of the 1946 negatives
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Safekeeping the 1946 originals
Left: Once Right: Now
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Number of scans 4117
Base Negative
Scan resolution 14 micron
Scanning the 1946 originals
Metadata
5. Processing
Image Orientation with HAP (Historical Air Photo), a module by PCI Geomatica.
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HAP Toolbar
Ingest Panel
GeoRef Panel
Alignment Panel
HAP Quality Assurance Interface
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OrthoEngine (Review GCPs/TPs) Mosaic Tool (Interactive Mosaic Editing)
Geomatica Toolbar
HAP Image Metadata Requirements
• Physical paper dimensions
• Height and width in inches
• Dimensions cannot vary more than %5 between photos
• Approximate flying altitude or scale
• Altitude in feet
• Approximate image centers
• Estimate of scene centers < 2 km (in our case: < 100m!)
• Longitude / Latitude (DD) WGS84
• Camera focal length
• Focal length in millimeters
Reference Data Requirements for HAP processing
• Reference image
• Resolution similar to uncorrected photos (1:5)
• Elevation model
• Resolution should be less than 1:10 ratio between DEM and
uncorrected photos
Automated data preparation with FME & Python
• Clipping & masking reference orthophoto etc.
Building the Internal Orientation
• Focal Length known (153.37 mm)
• No existing calibration files.
• No Fiducial Marks
• Calibration determined through manual
measurements of image ‘corners’ from
representative set of images
• Difficulties running automated fiducial
mark detection
Dist X Top Dist X Bot Dist Y Left Dist Y Right
16001.82 16008.30 15989.80 16012.70
15948.80 15955.01 15957.02 15971.11
15966.80 15969.80 15998.01 16005.81
16172.99 16169.11 16174.87 16181.58
16083.54 16091.42 16088.32 16100.13
16109.41 16101.40 16103.11 16111.40
16036.74 16048.69 16066.56 16086.53
16166.11 16166.11 16159.21 16165.11
16185.00 16171.30 16181.40 16179.70
16144.72 16128.33 16149.02 16144.20
16116.47 16124.68 16085.54 16150.22
16155.10 16150.71 16168.72 16164.43
16108.65 16109.40 16157.30 16183.81
16097.92 16089.60 16112.70 16132.60
16191.07 16157.02 16125.70 16148.92
16197.82 16166.30 16130.06 16157.11
16200.63 16157.30 16111.74 16137.20
16215.90 16178.72 16179.01 16204.81
16069.61 16091.70 16083.82 16091.88
16072.00 16079.13 16063.90 16093.00
16170.01 16154.02 16132.61 16139.50
16160.01 16134.11 16118.05 16122.21
16158.13 16134.54 16111.01 16116.30
16155.91 16167.43 16163.20 16204.70
mean 16120.19 16112.64 16108.76 16125.19
16120.21 16112.67 16108.78 16125.21
stddev 73.79 62.93 60.41 60.27
inch 8.88 8.88 8.88 8.88
mm 225.59 225.49 225.43 225.66
Typical block configuration
Yellow: Image centers Blue: Additional images (extra line or extended line) Red: Check Points
In total: 14 Photogrammetic blocks with 300-400 images each.
Image footprints
Running the HAP process results in 1) Huge number of automatically detected GCPs
and 2) Huge number of automatically detected TPs
Residuals on manual Check Points:
TP/GCP distribution on a single image
RMS Error on Check Points in [pixel] (left) and [m] (right) for a typical block
Quality assurance on the ortho-photo
Quality assurance on the ortho-photo
1946 Ortho Recent Ortho
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The mosaicking process
• Highly automated
• sw: INPHO Orthovista
• Manual improvement, minimizing cloud cover
6. Outlook
Our mission
Current:
around 400’000 aerial images (starting 1926) in the archives
329’885 images digitized & metadata collected
45’689 images oriented
4’117 images oriented for 1946 coverage
less than 1%! of the archives
My personal opinion:
“We should not rest until the last scanned image in the archives
is oriented, orthorectified and published”
Projection centers of 329’885 images already digitized images
Towards fully automated workflows
Historical Airphoto Workflow
Data Prep Data
Ingest
QA
GCPs/TPs
QA
GCPs/TPs
Coarse
Alignment
Fine
Alignment Generate
orthos
Manual Semi-Auto
Automatic
Optional Path
Interior
Orientation
Historical Airphoto Workflow
Block
definition
QA
GCPs/TPs
Coarse
Alignment
Fine
Alignment Generate
orthos
Manual Semi-Auto
Automatic
Optional Path
QA
GCPs/TPs
Interior
Orientation Data Prep
& Ingest
Original workflow
Current workflow by swisstopo
Application example: Historic Aerial Images from the 1980’s
Coverage of Switzerland through 10’800 stereo models
Historic Aerial Images from the 1980’s: Multiple coverage in the stereo models
Swiss Federal Institute for Forest, Snow and Landscape Research WSL
Country-wide Derived Surface Model from Historic Air Photos
Resolution 1 m x 1 m
Swiss Federal Institute for Forest, Snow and Landscape Research WSL
Country-wide Vegetation Height Model from Historic Air Photos
https://www.wsl.ch/de/projekte/pan3d-nationwide-3d-data-from-historical-aerial-imagery.html
Resolution 1 m x 1 m
Aletsch glacier – biggest glacier of the Alps: 1981 and today
-64 m
-1’180 m